The present disclosure is generally related to wellbore operations and, more particularly, to systems and methods of injecting steam into a wellbore.
Recovery of valuable hydrocarbons in some subterranean formations can sometimes be difficult due to a relatively high viscosity of the hydrocarbons and/or the presence of viscous tar sands in the formations. In particular, when a production well is drilled into a subterranean formation to recover oil residing therein, often little or no oil flows into the production well even if a natural or artificially induced pressure differential exists between the formation and the well. To overcome this problem, various thermal recovery techniques have been used to decrease the viscosity of the oil and/or the tar sands, thereby making the recovery of the oil easier.
Steam assisted gravity drainage (SAGD) is one such thermal recovery technique and utilizes steam to thermally stimulate viscous hydrocarbon production by injecting steam into the subterranean formation to the hydrocarbons residing therein. As the steam is injected into the surrounding subterranean formation, it contacts cold oil within the formation. The steam gives up heat to the oil it comes into contact with and condenses, and the oil absorbs the heat and becomes mobile as its viscosity is reduced. Accordingly, as the temperature of the oil increases, it is able to more easily flow to a production well to be produced to the surface.
The temperature of the steam during SAGD operations is highly affected by the hydrostatic head of the production of the heated hydrocarbons. As a result, it is advantageous to control the production flow and the steam injection. Moreover, the temperature limit of typical sealing systems is a limiting factor in the use of sliding side door type of technology.